Keyboard musical instrument with electromagnetic operation



' 1; z 507 May 10, 1927. A. H. MAITRE ET AL 6 8,

KEYBOARD MUSICAL INSTRUMENT WITH ELECTROMAGNETIC OPERATION Filed Sept. 20. 1923 llllll //VV/Y7'06S.'-- 4L 00: H5: r00 Mm ma? m A o AEGIDE HECTOR. MAETRE AND VICTOR HENRE GASTON MARTEN, Q RQUEII, CE.

KEYBOARD MUSICAL INSTRUMELTT WITH ELECTROMAGNETIC Application filed September 26, 1923, Serial Ito 663,806, ans in September 21 The present invention relates to a keyboard musical instrument with electromagnetic operation, of the type having a branch circuit with a key lever controlling contacts,

for each note and a member interrupting the passage of the current through this part of the circuit at the desirecii frequency corresponding to this note.

In such musical instruments, is known to employ tuning forks for interrogating the current at the desireot frequency, it is also known to employ sound reproducing devices, such as telephones, megophones or the iike, as well as to employ resistances for regulaing the intensity of the sound thus reprodiuced,

@ur invention is characterized by the fact that the pulsations of current, produced by the operation of a key corresponciing to one note, are sent simultaneously to one or" more megaphones, telephones or the like, mounted. in a part of the circuit common to a groupof notes, and. to an eiectrornagnet specioi for each note and facing a suitably tuned magnetic vibrating sonorous body, such as a piano string,

By means of separate rheostats it is possibie in the known manner to regulate sop arateiy, and as desired, the intensity of the sound; producedl e the megaphones, teiephones or the anol the intensity of the sound produced by the strings or other mag tactic vibrating sonorous bodies, in; suciz s, Way that the sound produced by one of these sonorous bodies, tor exempts the mega homes or the like, can 'bcecicieci, with art intensity variable st Witt, the sound. prociuceo i Pay the other, for exempts the or the like, in no group of notes or in. several groups of tee:

The advantage o1 'foiiowiiig wet in @o; the one i tion of piano s tions of the thin as he t of the string, is eat I strings giving sleep 11 in this c sounci obtained. is sstisiactory, e'v synchrooisin the two rug time feet But the setting in viioratioo oz strings in the trebie necessitates ocii cction of synchronism that-is verydifiicoit to ob min in practice. The result in the techie is therefore unsatisfactory and at great toss of complete the resuits which each of the two methods is capabie of producing seperziteiy,

in the'rirawings, Fig. I; is an elevation one term ot construction of the arrangement according to our invention showing one group of notes of the instrument;

Fig. 2 is a plan View, seen too s the tuning fork anti of the interi vice which produces snot controis magnetic vibration of the tuning ig. 3 is a perspective View pairs of contacts actuated Toy 2t ar keyboard,

In Fig" ;t, the tuning fork electromagnetic means sustaining the vibration thereof, are shown in foil one note and diogrammaticaity for the other notes.

Beneath each key D (Fig, oi" the keyboard there are arranged two contacts nameiy, A, B, C, a a and A B ti a acieptedl tho-cooperate with fixed contacts c, e, c, n and. a, (2 respectiveiy when the key is depressed. designates o Vibrating boo adaptett to interrupt the current at the frequency of the cotresponcting note This vibrating body is ShQVi t't as a tuning fork ot which the vibrations are sustained eiectricaL i by the eiectizoairagiiet To each vi orator there correspond two contact pieces E E making on "ageroent with at each vibrstioo of the it, We,

these pieces E distributes the pulsations of current to one or more es, teiepiiofoes or the iike H in part of the circuit common to v The other contact piece EJ111593 the poisations of current to iectrornagnet L, speciai for each inciinote and pieced facing s magnetic "with toe corresponding note, for example a piano string M, A theostat is pieced in series with the electromagnets L is a part of the citiicit common to the gtoup of notes sonorous body tuned in unison under consideration. R is a rheostat placed in parallel to the megaphones H or the like, in the part of the circuit common to the group of notes.

The electromagnet K, which actuates the tuning fork F, comprises two coils in'series, (see upper part of Figs. 1 and 2). The contact piece E is carried by a movable arm E secured to a shaft E journalled in two bearings E. This movable arm E carries an iron blade E, adapted to be attracted by the electro-magnet K; this attraction producing forced breaks of current between E and F. A piston E immersed in a viscous liquid E contained in a vessel E of a small sectional area, damps the oscillations of the movable arm E Due to this quick dampening the tuning fork F soon becomes its own interrupting device.

The contact piece E is also pivotally mounted (see upper part of Fig. 1); its inertia during the vibration of the tuning fork F producing making of contact followed by breaking of contact of the same rhythm as the vibration of the tuningfork.

The mechanism operates in the manner which will now be described. i When a key of the keyboard is pressed, it closes a contact such asAa and a second contact such as A-a the current flows from the contact Aa to the vibrator F and there divides, one portion passing by the contact E which presses upon the vibrator F when the latter is at rest, traverses the electromagnet L and the rheostat R and returns to the sourpe of current. The second portion of the current passes by the contact E, which also presses upon the vibrator when the latter is at rest, traverses the electro-magnet K, then passes the megaphones H and the rheostat R and returns to the source. The passage of the current through the electro-magnet K starts the vibrator F in movement; and at this moment, pulsations of current are sent by the contact E to the megaphones H and by the contact E to the corresponding electromagnet L. The megaphones H and the strings M sound simultaneously with intensities variableat will or separately, according to the resistance given to the rheostats. Thus, when the resistance of the rheostat R is nil, the strings M alone sound, for the megaphone or megaphones H is or are short circuited but if the resistance R is not nil and if the resistance R is very great, or if the circuit is broken at R the megaphone or megaphones H will alone sound.

It is thus possible, by suitable regulation of the rheostats R and R corresponding to the different groups of notes, to cause in any one group of notes a predominance as desired of the sonorous bodies of one given type, either the telephones or megaphones or the like H or the piano strings M or the like, and at the same time it is possible to causea predominance in another group of notes of the sonorous bodies of different type.

What We claim is:

1. A keyboard musical instrument with electromagnetic operation, comprising a circuit common to all the notes of the instrument and a key for each note, contacts actuated by said key, a branch circuit, an interrupter device controlled by said contacts and adapted to interrupt the flow of current in this branch circuit at the desired frequency corresponding to this note, a part of circuit common to a group of notes, sound reproducing devices mounted in said common part of circuit, and a first contact member adapted to cooperate with the interrupter device in a part of each branch circuit corresponding to a note and to distribute pulsations of current to said sound reproducing devices, together with a vibrating sonorous body tuned in unison with the corresponding note in a second part of each branch circuit, electromagnetic means for vibrating said sonorous body in said branch circuit, and a second contact member adapted to cooperate with the interrupter device and to distribute pulsations of current to said electromagnetic means in each branch circuit, forv the purpose described.

2. A keyboard musical instrument with electromagnetic operation, comprising a circuit common to all the notes of the instrument and a key for each note, contacts actuated by said key, a branch circuit, an interrupter device controlled by said contacts and adapted to interrupt the flow of current in this branch circuit at the desired frequency corresponding to this note, a part of circuit common to a group of notes, sound reproducing devices mounted in said common part of circuit, and a first contact meme ber adapted to cooperate with the interrupter device in a part of each branch circuit corresponding to a note and to distribute pulsations of current to said sound reproducing devices, means in said common part of circuit for regulating the intensity of the sound produced by the said sound reproducing devices, together with a vibrating sonorous body'tuned in unison with the corresponding note in a second part of each branch circuit, electromagnetic means for vibrating said sonorous body in said branch circuit, and a second contact member adapted to cooperate with the interrupter device and to distribute pulsations of current to said electromagnetic means in each branch circuit, another part of circuit common to the same group of notes, and means in said common part of circuit for regulating the intensity of the sound produced by the vibrating sonorous bodies corresp1 nding to the notes of said group, for t e purpose described.

3. A keyboard musical instrument with electromagnetic operation, comprising a circuit common to all the notes of the instrument and a key for each note, contacts actuated by said key, a branch circuit, a tuning fork controlled by said contacts and adapted to interrupt the flow of current in said branch circuit at the frequency corresponding to this note, an electromagnet for vibrating said tuning fork, a part of circuit common to a group of notes, telephones mounted in said common part of circuit, a first contact member adapted to cooperate with the tuning fork in a part of each branch circuit corresponding to a note and to distribute pulsations of current to said telephones, and a rheostat in said common part of circuit for regulating the intensity of the sound produced by the said telephones,

together with a string tuned in unison with the corresponding note in a second part of each branch circuit, an electromagnet for vibrating said string in said branch circuit, a second contact member adapted to cooperate with the tuning fork in said second part of each branch circuit and to distribute pulsations of current to said electroniagnet in each branch circuit, another part of circuit common to the same group of notes, and a rheostat in said common part of circuit for regulating the intensity of. the sound produced by the strings corresponding to thenotes of said group; for the purpose described In testimony whereof we have signed our names to this specification.

ALQIDE HECTOR MAITRE.

VICTOR HENRI GASTON MARTIN. 

